Prevalence of low-grade inflammation in depression: a systematic review and meta-analysis of CRP levels

Circadian depression: A mood disorder phenotype

Major mood syndromes are among the most common and disabling mental disorders. However, a lack of clear delineation of their underlying pathophysiological mechanisms is a major barrier to prevention and optimised treatments. Dysfunction of the 24-h circadian system is a candidate mechanism that has genetic, behavioural, and neurobiological links to mood syndromes. Here, we outline evidence for a new clinical phenotype, which we have called 'circadian depression'. We propose that key clinical characteristics of circadian depression include disrupted 24-h sleep-wake cycles, reduced motor activity, low subjective energy, and weight gain. The illness course includes early age-of-onset, phenomena suggestive of bipolarity (defined by bidirectional associations between objective motor and subjective energy/mood states), poor response to conventional antidepressant medications, and concurrent cardiometabolic and inflammatory disturbances. Identifying this phenotype could be clinically valuable, as circadian-targeted strategies show promise for reducing depressive symptoms and stabilising illness course. Further investigation of underlying circadian disturbances in mood syndromes is needed to evaluate the clinical utility of this phenotype and guide the optimal use of circadian-targeted interventions.

The Immunology of Stress and the Impact of Inflammation on the Brain and Behavior

Exposure to acute versus chronic stressors and threats activates the immune system in adaptive and maladaptive manners, respectively. While acute activation of the immune system in response to threat is homeostatically regulated by glucocorticoid negative feedback, chronic activation of the immune system arising from persistent stress exposure can contribute to an allostatic load with an inflammatory diathesis that has been implicated in stress-related psychopathology, including of depression and anxiety. Increased inflammation in the periphery and in the brain arising from chronic stress exposure can alter neurotransmitter metabolism and impact activation of brain regions to increase adverse behavioral health symptoms (e.g. anhedonia, anxiety, fatigue) and emotion dysregulation. While interventions targeting the immune system and its downstream effects on the brain for the treatment of depression and other psychiatric disorders has been of great interest as they have shown some efficacy in treating stress-related behavioral health disorders, future studies are necessary to better characterize the contexts under which anti-inflammatory agents should be used to treat stress-related psychopathology.

Is dynapenia associated with the onset and persistence of depressive and anxiety symptoms among older adults? Findings from the Irish longitudinal study on ageing

OBJECTIVES

The aim of the current study was to assess the associations between dynapenia and the onset and persistence of depression and anxiety among older adults.

METHODS

This prospective cohort study enrolled community-living older adults (N = 5271; 51.1% females) aged ≥ 50 years (mean age = 63.2, standard deviation = 9.0) from The Irish Longitudinal Study on Aging (TILDA), Ireland. At baseline, participants completed a handgrip assessment. Depression was defined by a score ≥ 16 in the Center of Epidemiology Studies Depression (CES-D) tool and anxiety was considered when participants scored ≥ 8 on the anxiety section of the Hospital Anxiety and Depression Scale (HADS). Outcomes were incident and persistent depression and anxiety at two years follow-up. Multivariable logistic regression models were built for each outcome.

RESULTS

After controlling for age, sex, education, marital status, employment status, smoking, body mass index, number of chronic conditions, physical activity, and cognitive function, low handgrip strength indicative of dyapenia (< 30 Kg for men and < 20 Kg for women) was associated with a greater likelihood for incident depressive (OR = 1.44; 95%CI: 1.08-1.92) as well as for persistent depressive (OR = 1.61; 95% CI: 1.01-2.58) and anxiety (OR = 1.61; 95% CI: 1.20-2.14) symptoms.

CONCLUSIONS

Dynapenia was associated with a higher odds of developing depressive symptoms as well as a greater likelihood to persistent depressive and anxiety symptoms among older adults. Our data suggest that interventions targeting muscle strength may prevent the onset of late-life depression and also may hold promise as novel therapeutic opportunities for depression and anxiety in later life.

Plasma metabolites were associated with spatial working memory in major depressive disorder

Major depressive disorder (MDD) is a common disease with both affective and cognitive disorders. Alterations in metabolic systems of MDD patients have been reported, but the underlying mechanisms still remains unclear. We sought to identify abnormal metabolites in MDD by metabolomics and to explore the association between differential metabolites and neurocognitive dysfunction.Plasma samples from 53 MDD patients and 83 sex-, gender-, BMI-matched healthy controls (HCs) were collected. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) system was then used to detect metabolites in those samples. Two different algorithms were applied to identify differential metabolites in 2 groups. Of the 136 participants, 35 MDD patients and 48 HCs had completed spatial working memory test. Spearman rank correlation coefficient was applied to explore the relationship between differential metabolites and working memory in these 2 groups.The top 5 metabolites which were found in sparse partial least squares-discriminant analysis (sPLS-DA) model and random forest (RF) model were the same, and significant difference was found in 3 metabolites between MDD and HCs, namely, gamma-glutamyl leucine, leucine-enkephalin, and valeric acid. In addition, MDD patients had higher scores in spatial working memory (SWM) between errors and total errors than HCs. Valeric acid was positively correlated with working memory in MDD group.Gamma-glutamyl leucine, leucine-enkephalin, and valeric acid were preliminarily proven to be decreased in MDD patients. In addition, MDD patients performed worse in working memory than HCs. Dysfunction in working memory of MDD individuals was associated with valeric acid.

Treatment-Resistant Depression Revisited: A Glimmer of Hope

Major Depressive Disorder (MDD) is a highly prevalent psychiatric disorder worldwide. It causes individual suffering, loss of productivity, increased health care costs and high suicide risk. Current pharmacologic interventions fail to produce at least partial response to approximately one third of these patients, and remission is obtained in approximately 30% of patients. This is known as Treatment-Resistant Depression (TRD). The burden of TRD exponentially increases the longer it persists, with a higher risk of impaired functional and social functioning, vast losses in quality of life and significant risk of somatic morbidity and suicidality. Different approaches have been suggested and utilized, but the results have not been encouraging. In this review article, we present new approaches to identify and correct potential causes of TRD, thereby reducing its prevalence and with it the overall burden of this disease entity. We will address potential contributory factors to TRD, most of which can be investigated in many laboratories as routine tests. We discuss endocrinological aberrations, notably, hypothalamic-pituitary-adrenal (HPA) axis dysregulation and thyroid and gonadal dysfunction. We address the role of Vitamin D in contributing to depression. Pharmacogenomic testing is being increasingly used to determine Single Nucleotide Polymorphisms in Cytochrome P450, Serotonin Transporter, COMT, folic acid conversion (MTHFR). As the role of immune system dysregulation is being recognized as potentially a major contributory factor to TRD, the measurement of C-reactive protein (CRP) and select immune biomarkers, where testing is available, can guide combination treatments with anti-inflammatory agents (e.g., selective COX-2 inhibitors) reversing treatment resistance. We focus on established and emerging test procedures, potential biomarkers and non-biologic assessments and interventions to apply personalized medicine to effectively manage treatment resistance in general and TRD specifically.

Structural brain correlates of serum and epigenetic markers of inflammation in major depressive disorder

Inflammatory processes are implicated in the aetiology of Major Depressive Disorder (MDD); however, the relationship between peripheral inflammation, brain structure and depression remains unclear, partly due to complexities around the use of acute/phasic inflammatory biomarkers. Here, we report the first large-scale study of both serological and methylomic signatures of CRP (considered to represent acute and chronic measures of inflammation respectively) and their associations with depression status/symptoms, and structural neuroimaging phenotypes (T1 and diffusion MRI) in a large community-based sample (Generation Scotland; NMDD cases = 271, Ncontrols = 609). Serum CRP was associated with overall MDD severity, and specifically with current somatic symptoms- general interest (β = 0.145, PFDR = 6 × 10-4) and energy levels (β = 0.101, PFDR = 0.027), along with reduced entorhinal cortex thickness (β = -0.095, PFDR = 0.037). DNAm CRP was significantly associated with reduced global grey matter/cortical volume and widespread reductions in integrity of 16/24 white matter tracts (with greatest regional effects in the external and internal capsules, βFA= -0.12 to -0.14). In general, the methylation-based measures showed stronger associations with imaging metrics than serum-based CRP measures (βaverage = -0.15 versus βaverage = 0.01 respectively). These findings provide evidence for central effects of peripheral inflammation from both serological and epigenetic markers of inflammation, including in brain regions previously implicated in depression. This suggests that these imaging measures may be involved in the relationship between peripheral inflammation and somatic/depressive symptoms. Notably, greater effects on brain morphology were seen for methylation-based rather than serum-based measures of inflammation, indicating the importance of such measures for future studies.

Dissecting the Association Between Inflammation, Metabolic Dysregulation, and Specific Depressive Symptoms: A Genetic Correlation and 2-Sample Mendelian Randomization Study

IMPORTANCE

Observational studies highlight associations of C-reactive protein (CRP), a general marker of inflammation, and interleukin 6 (IL-6), a cytokine-stimulating CRP production, with individual depressive symptoms. However, it is unclear whether inflammatory activity is associated with individual depressive symptoms and to what extent metabolic dysregulation underlies the reported associations.

OBJECTIVE

To explore the genetic overlap and associations between inflammatory activity, metabolic dysregulation, and individual depressive symptoms.

GWAS DATA SOURCES

Genome-wide association study (GWAS) summary data of European individuals, including the following: CRP levels (204 402 individuals); 9 individual depressive symptoms (3 of which did not differentiate between underlying diametrically opposite symptoms [eg, insomnia and hypersomnia]) as measured with the Patient Health Questionnaire 9 (up to 117 907 individuals); summary statistics for major depression, including and excluding UK Biobank participants, resulting in sample sizes of 500 199 and up to 230 214 individuals, respectively; insomnia (up to 386 533 individuals); body mass index (BMI) (up to 322 154 individuals); and height (up to 253 280 individuals).

DESIGN

In this genetic correlation and 2-sample mendelian randomization (MR) study, linkage disequilibrium score (LDSC) regression was applied to infer single-nucleotide variant-based heritability and genetic correlation estimates. Two-sample MR tested potential causal associations of genetic variants associated with CRP levels, IL-6 signaling, and BMI with depressive symptoms. The study dates were November 2019 to April 2020.

RESULTS

Based on large GWAS data sources, genetic correlation analyses revealed consistent false discovery rate (FDR)-controlled associations (genetic correlation range, 0.152-0.362; FDR P = .006 to P < .001) between CRP levels and depressive symptoms that were similar in size to genetic correlations of BMI with depressive symptoms. Two-sample MR analyses suggested that genetic upregulation of IL-6 signaling was associated with suicidality (estimate [SE], 0.035 [0.010]; FDR plus Bonferroni correction P = .01), a finding that remained stable across statistical models and sensitivity analyses using alternative instrument selection strategies. Mendelian randomization analyses did not consistently show associations of higher CRP levels or IL-6 signaling with other depressive symptoms, but higher BMI was associated with anhedonia, tiredness, changes in appetite, and feelings of inadequacy.

CONCLUSIONS AND RELEVANCE

This study reports coheritability between CRP levels and individual depressive symptoms, which may result from the potentially causal association of metabolic dysregulation with anhedonia, tiredness, changes in appetite, and feelings of inadequacy. The study also found that IL-6 signaling is associated with suicidality. These findings may have clinical implications, highlighting the potential of anti-inflammatory approaches, especially IL-6 blockade, as a putative strategy for suicide prevention.

A Modest Increase in 11C-PK11195-Positron Emission Tomography TSPO Binding in Depression Is Not Associated With Serum C-Reactive Protein or Body Mass Index

Background

Immune mechanisms have been implicated in the pathogenesis of depression. Translocator protein (TSPO)–targeted positron emission tomography (PET) has been used to assess neuroinflammation in major depressive disorder. We aimed to 1) test the hypothesis of significant case-control differences in TSPO binding in the anterior cingulate cortex, prefrontal cortex, and insula regions; and 2) explore the relationship between cerebral TSPO binding and peripheral blood C-reactive protein (CRP) concentration.

Methods

A total of 51 depressed subjects with Hamilton Depression Rating Scale score >13 (median 17; interquartile range, 16–22) and 25 healthy control subjects underwent dynamic brain ¹¹C-PK11195 PET and peripheral blood immune marker characterization. Depressed subjects were divided into high CRP (>3 mg/L; n = 20) and low CRP (<3 mg/L; n = 31).

Results

Across the three regions, TSPO binding was significantly increased in depressed versus control subjects (η²_p = .09; F_1,71 = 6.97, p = .01), which was not influenced by body mass index. The case-control difference was greatest in the anterior cingulate cortex (d = 0.49; t₇₄ = 2.00, p = .03) and not significant in the prefrontal cortex or insula (d = 0.27 and d = 0.36, respectively). Following CRP stratification, significantly higher TSPO binding was observed in low-CRP depression compared with controls (d = 0.53; t₅₄ = 1.96, p = .03). These effect sizes are comparable to prior major depressive disorder case-control TSPO PET data. No significant correlations were observed between TSPO and CRP measures.

Conclusions

Consistent with previous findings, there is a modest increase in TSPO binding in depressed patients compared with healthy control subjects. The lack of a significant correlation between brain TSPO binding and blood CRP concentration or body mass index poses questions about the interactions between central and peripheral immune responses in the pathogenesis of depression.

Inflammation predicts new onset of depression in men, but not in women within a prospective, representative community cohort

Depression has been associated with increased inflammation. However, only few large-scale, prospective studies have evaluated whether inflammation leads to new cases of depression and whether this association can be found in men and women. Longitudinal data of N = 10,357 adult participants with no evidence of depression at baseline (based on Patient Health Questionnaire (PHQ-9), lifetime diagnoses, and current antidepressant medication) were evaluated for depression 5 years later. Multivariate logistic regression models were used to predict the onset of depression based on C-reactive protein (CRP) and white blood cell count (WBC). We used interaction terms and separate analyses in men and women to investigate gender-dependent associations. Based on both markers, inflammation was predictive of new cases of depression 5 years later, even when adjusting for sociodemographic, physical health, health behavior variables, and baseline depression symptoms. As established by interaction terms and separate analyses, inflammatory markers were predictive of depression in men, but not in women. Additional predictors of new onset of depression were younger age, loneliness, smoking (only in men), cancer and less alcohol consumption (only in women). The study indicates gender differences in the etiology of depressive disorders within the community, with a greater role of physical factors in men.

Predictive inflammatory biomarkers for change in suicidal ideation in major depressive disorder and panic disorder: A 12-week follow-up study

Previous studies have investigated the role of inflammatory markers in suicidality of patients with major depressive disorder (MDD) or panic disorder (PD). However, few studies have investigated associations between serum inflammatory cytokine levels and suicidality. We hypothesized that MDD and PD status might be significantly associated with serum inflammatory cytokines and that we could predict levels of improvement in suicide ideation intensity using serum inflammatory biomarkers in patients with MDD and PD. For this study, 41 patients with MDD, 52 patients with PD, and 59 healthy control (HC) subjects were enrolled. Psychological measurements and serum inflammatory markers such as interleukin (IL) -6, -10, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and C reactive protein (CRP) were examined. A total of five visits were completed during 12 weeks. After controlling for confounding factors, log-transformed IL-6 (ln_IL-6) at baseline (MDD: 0.297 ± 0.626; PD: 0.342 ± 0.723; HC: -0.121 ± 0.858; p = 0.007, >0.0017, 0.05/30) and mean ln_IL-6 (MDD: 0.395 ± 0.550, PD: 0.249 ± 0.544, HC: -0.139 ± 0.622, p = 0.002, >0.0017, 0.05/30) levels were trends towards significantly higher in patients with MDD and PD than in HC. In MDD patients, a higher level of basal ln_TNF-α was a significant predictor of ΔSSI (changes in SSI scores between baseline and week 12) even after controlling for changes of depression symptoms and baseline SSI scores (standardized β = 0.541, p = 0.002 < 0.0028, 0.05/18). In conclusion, we could predict ΔSSI using baseline inflammatory biomarkers for patients with MDD.

IL-8 and CRP moderate the effects of preoperative psychological interventions on postoperative long-term outcomes 6 months after CABG surgery - The randomized controlled PSY-HEART trial

INTRODUCTION

Inflammation has been related to several somatic and psychological disorders and may moderate effects of psychological interventions. In the PSY-HEART trial patients benefitted from preoperative psychological interventions before undergoing coronary artery bypass graft surgery (CABG) and, if necessary, concomitant valvular surgery, compared to standard medical care. In this study we examined whether patients' baseline inflammatory status moderated the intervention effects.

MATERIAL AND METHODS

In a prospective three-arm randomized clinical trial with 6-months follow-up, 124 patients scheduled for CABG surgery alone or concomitant with valvular surgery were randomized to (i) standard medical care only (SMC) or two preoperative psychological interventions: (ii) CBT-based optimizing expectations (EXPECT) and an (iii) an active control group focusing on emotional support (SUPPORT). Available baseline CRP- (n = 79), IL-6- (n = 78), IL-8- (n = 78) and TNF-alpha-(n = 80) parameters were considered as potential moderators (CRP as a categorical and continuous moderator). Linear mixed model analyses were calculated to test whether baseline inflammatory levels moderated intervention effects on disability, mental and physical quality of life at 6 months after surgery.

RESULTS

IL-8 moderated intervention effects on patients' disability and categorical CRP moderated intervention effects on mental quality of life. Follow-up tests indicated that EXPECT (and in part SUPPORT) led to lower postoperative disability and higher mental quality of life compared to SMC in patients with low baseline inflammatory markers. EXPECT indicated higher mental quality of life compared to SUPPORT in the high CRP subgroup. Patients in the SMC group had higher mental quality of life in the high CRP subgroup compared to the low CRP subgroup.

CONCLUSION

Especially for patients with a lower inflammatory baseline status preoperative psychological interventions might be helpful to optimize long-term CABG surgery outcomes.

Inflammatory processes linked to major depression and schizophrenic disorders and the effects of polypharmacy in psychiatry: evidence from a longitudinal study of 279 patients under therapy

Over the past 2 decades, polypharmacy has become the de-facto standard of acute treatment in psychiatry where patients with psychiatric disorders receive a multiple medication regimen. There is growing evidence for a potential link between major psychiatric disorders and inflammatory processes. Combining these two aspects aims at avoiding polypharmacy attempts among patients with inflammatory activation through alternative treatment strategies. In this study, we addressed the following questions: (1) to what extent can polypharmacy be explained through the factors "diagnosis", "previous history", "severity at baseline", "age", "gender", and "psychiatrist in charge"; (2) what are the differences between polypharmacy and monotherapy regarding efficacy and side effect profiles; and (3) what amount of between-patient variance is explainable by the natural antibody immunoglobulin M (IgM) within each diagnostic group. This naturalistic longitudinal study was comprised of 279 patients under therapy with a clinical diagnosis of depressive (ICD-10: "F3x.x"; n = 195) or schizophrenic disorders (ICD-10: "F2x.x"; n = 84). The study protocol included (1) assessment of previous history by the SADS Syndrome Check List SSCL-16 (lifetime version); (2) repeated measurements over 5 weeks assessing the time course of improvement by the Hamilton Depression Scale HAM-D and the Positive and Negative Syndrome Scale PANSS, along with medication and unwanted side effects through the Medication and Side Effects Inventory MEDIS; and (3) the collection of blood samples from which DNA and serum were extracted. The association between inflammatory response system and psychiatric disorders was detailed by fitting multi-layer Neural Net (NN) models to the observed data ("supervised learning"). The same approach was used to set up prediction models of side effects. Our data showed that polypharmacy was omnipresent. Yet the various polypharmacy regimens had no advantage over monotherapy: we even found slightly larger baseline score reductions under monotherapy, independent of primary diagnoses and for comparable baseline severities. Most patients experienced unwanted side effects. The close link between side effects and treatment regimen was revealed by a linear model in which the mere number of drugs explained a significant (p < 0.001) proportion of the observed variance. As to the inflammatory response system: For the F2 patients, our NN model identified a 22.5% subgroup exhibiting a significant correlation of r = 0.746 (p = 0.0004) between global schizophrenia scores and IgM levels, along with a correct prediction of response of 94.4%, thus explaining 55.7% of the observed between-patient variance. For the F3 patients, our NN model identified a 19.6% subgroup exhibiting a significant correlation of r = 0.644 (p = 0.00003) between global depression scores and IgM levels, along a correct prediction of response of 89.6%, thus explaining 41.4% of the observed between-patient variance. Polypharmacy is omnipresent in today's acute treatment of psychiatric disorders. Given the large proportion of patients with unwanted side effects and the strong correlation between side effects and the number of drugs, polypharmacy approaches are not equally suited for every patient. In terms of efficacy, there are no advantages of polypharmacy over monotherapy. Most notably, our study appears to have cleared the way for the reliable identification of a subgroup of patients for whom the inflammatory response system is a promising target of therapeutic intervention.

Childhood Adversities and Salivary Cortisol Responses to the Trier Social Stress Test: A Systematic Review of Studies Using the Children Trauma Questionnaire (CTQ)

Alteration in cortisol response to acute social stressors has been hypothesized to mediate childhood adversities (CA) and increased morbidity in adulthood. However, the evidence supporting an association between CA and cortisol response to social stressors is inconclusive. The present review addressed this issue by reviewing the literature on CA and cortisol response to acute social stressors, with a focus on studies with adolescents or adults, using the Childhood Trauma Questionnaire (CTQ) to assess CA, and examining salivary cortisol response to the Trier Social Stress Test (TSST). Systematic searches of relevant articles in PsycINFO, PubMed, Web of Science and ScienceDirect in February and March 2020 identified 12 articles including 1196 participants with mean ages ranging from 15.3 to 52.3 yrs. across studies. CTQ scores were significantly associated with cortisol response in 2 studies. In addition, the physical abuse and emotional neglect subscales were associated with cortisol response respectively in 2 separate studies. The lack of association between CA and cortisol response calls for more longitudinal studies, and the use of formal records of maltreatment or informant reports in future research to complement information collected by retrospective measures. In addition, increased attention to biological mechanisms other than that associated with the regulation of cortisol in explaining the connection between CA and psychiatry morbidity is warranted.

Novel neuronal surface autoantibodies in plasma of patients with depression and anxiety

Neuronal surface autoantibodies (NSAbs) against various antigens cause autoimmune encephalitis. Some of these antigens are also involved in the pathology of depression and anxiety. To study whether NSAbs are more common in plasma of individuals with depression and anxiety than in controls, and to investigate if NSAbs correlate with disease status, plasma samples of 819 individuals with a current diagnosis of depression and/or anxiety, 920 in remission and 492 individuals without these disorders were included in this study. Samples were tested by a combination of immunohistochemistry (IHC), staining on live rat hippocampus neurons and cell-based assay (CBA). By IHC, 50 (2.2%) samples showed immunoreactivity to rat brain tissue, with no significant differences between the aforementioned groups (22/819 vs 18/920 vs 11/492, P > 0.99). In addition, eight IHC positive samples were positive for NSAbs on live neurons (7/819 vs 0/920 vs 1/492, P = 0.006). The IHC-staining patterns of these eight samples were atypical for autoimmune encephalitis and accordingly, they tested negative for known NSAbs by CBA. No obvious difference in the clinical characteristics between individuals with or without NSAbs was observed. In conclusion, novel NSAbs were rare but predominately found in patients with current anxiety or depression indicating they might affect mental health in a small group of patients.

Anti-inflammatory activity of ayahuasca: therapeutical implications in neurological and psychiatric diseases

Ayahuasca is a decoction with psychoactive properties, used for millennia for therapeutic and religious purposes by indigenous groups and the population of amazonian countries. As described in this narrative review, it is essentially constituted by β-carbolines and tryptamines, and it has therapeutic effects on behavioral disorders due to the inhibition of the monoamine oxidase enzyme and the activation of 5-hydroxytryptamine receptors, demonstrated through preclinical and clinical studies. It was recently observed that the pharmacological response presented by ayahuasca is linked to its anti-inflammatory action, attributed mainly to dimethyltryptamines (N, N-dimethyltryptamine and 5-methoxy-N, N-dimethyltryptamine), which act as endogenous systemic regulators of inflammation and immune homeostasis, also through sigma-1 receptors. Therefore, since neuroinflammation is among the main pathophysiological mechanisms related to the development of neurological and psychiatric diseases, we suggest, based on the available evidence, that ayahuasca is a promising and very safe therapeutic strategy since extremely high doses are required to reach toxicity. However, even so, additional studies are needed to confirm such evidence, as well as the complete elucidation of the mechanisms involved.

Depression in patients with spondyloarthritis: prevalence, incidence, risk factors, mechanisms and management

Depression is a major neuropsychiatric disorder common in patients with rheumatological conditions including spondyloarthritis (SpA). It is associated with higher disease activity, functional impairment, poor treatment response and quality of life in patients with musculoskeletal disorders. Using ankylosing spondylitis (AS) and psoriatic arthritis (PsA) as examples, we have reviewed the evidence regarding the burden, risk factors, potential mechanisms and clinical management of depression in spondyloarthritis. The prevalence of depression is higher in patients with AS and PsA compared with the general population, with evidence of moderate/severe depression in about 15% of patients with AS or PsA. Mild depression is even more common and estimated to be present in about 40% of patients with AS. In addition to conventional risk factors such as stressful life events and socioeconomic deprivation, increased risk of depression in SpA may be associated with disease-related factors, such as disease activity, poor quality of life, fatigue, and sleep disturbances. Emerging evidence implicates inflammation in the aetiology of depression, which could also be a shared mechanism for depression and chronic inflammatory conditions such as AS and PsA. It is imperative for clinicians to actively assess and treat depression in SpA, as this could improve treatment adherence, quality of life, and overall long-term clinical and occupational outcomes. The use of validated tools can aid recognition and management of depression in rheumatology clinics. Management of depression in SpA, especially when to refer to specialist mental health services, are discussed.

Post-inflammatory behavioural despair in male mice is associated with reduced cortical glutamate-glutamine ratios, and circulating lipid and energy metabolites

Post-inflammatory behaviours in rodents are widely used to model human depression and to test the efficacy of novel anti-depressants. Mice injected with lipopolysaccharide (LPS) display a depressive-like phenotype twenty-four hours after endotoxin administration. Despite the widespread use of this model, the mechanisms that underlie the persistent behavioural changes after the transient peripheral inflammatory response remain elusive. The study of the metabolome, the collection of all the small molecule metabolites in a sample, combined with multivariate statistical techniques provides a way of studying biochemical pathways influenced by an LPS challenge. Adult male CD-1 mice received an intraperitoneal injection of either LPS (0.83 mg/kg) or saline, and were assessed for depressive-like behaviour 24 h later. In a separate mouse cohort, pro-inflammatory cytokine gene expression and 1H nuclear magnetic resonance (NMR) metabolomics measurements were made in brain tissue and blood. Statistical analyses included Independent Sample t-tests for gene expression data, and supervised multi-variate analysis using orthogonal partial least squares discriminant analysis for metabolomics. Both plasma and brain metabolites in male mice were altered following a single peripheral LPS challenge that led to depressive-like behaviour in the forced swim test. The plasma metabolites altered by LPS are involved in energy metabolism, including lipoproteins, glucose, creatine, and isoleucine. In the brain, glutamate, serine, and N-acetylaspartate (NAA) were reduced after LPS, whereas glutamine was increased. Serine-modulated glutamatergic signalling and changes in bioenergetics may mediate the behavioural phenotype induced by LPS. In light of other data supporting a central imbalance of glutamate-glutamine cycling in depression, our results suggest that aberrant central glutaminergic signalling may underpin the depressive-like behaviours that result from both inflammation and non-immune pathophysiology. Normalising glutaminergic signalling, rather than seeking to increase serotonergic signalling, might prove to be a more coherent approach to the development of new treatments for mood disorder.

Can selective serotonin reuptake inhibitors have a neuroprotective effect during COVID-19?

The absence of a specific treatment for SARS-CoV-2 infection led to an intense global effort in order to find new therapeutic interventions and improve patient outcomes. One important feature of COVID-19 pathophysiology is the activation of immune cells, with consequent massive production and release of inflammatory mediators that may cause impairment of several organ functions, including the brain. In addition to its classical role as a neurotransmitter, serotonin (5-hydroxytryptamine, 5-HT) has immunomodulatory properties, downregulating the inflammatory response by central and peripheral mechanisms. In this review, we describe the roles of 5-HT in the regulation of systemic inflammation and the potential benefits of the use of specific serotonin reuptake inhibitors as a coadjutant therapy to attenuate neurological complications of COVID-19.

Changes in inflammatory biomarkers are related to the antidepressant effects of Ayahuasca

BACKGROUND

Ayahuasca is a traditional Amazon brew and its potential antidepressant properties have recently been explored in scientific settings. We conducted a double-blind placebo-controlled trial of ayahuasca with treatment-resistant depression patients (n = 28) and healthy controls (n = 45).

AIMS

We are evaluating the blood inflammatory biomarkers: C-reactive protein and interleukin 6, as a potential consequence of ayahuasca intake and their correlation with serum cortisol and brain-derived neurotrophic factor levels. Blood samples were collected at pre-treatment and 48 hours after substance ingestion to assess the concentration of inflammatory biomarkers, together with administration of the Montgomery-Åsberg Depression Rating Scale.

RESULTS

At pre-treatment, patients showed higher C-reactive protein levels than healthy controls and a significant negative correlation between C-reactive protein and serum cortisol levels was revealed (rho = -0.40, n = 14). C-reactive protein in those patients was not correlated with Montgomery-Åsberg Depression Rating Scale scores. We observed a significant reduction of C-reactive protein levels across time in both patients and controls treated with ayahuasca, but not with placebo. Patients treated with ayahuasca showed a significant correlation (rho = + 0.57) between larger reductions of C-reactive protein and lower depressive symptoms at 48 hours after substance ingestion (Montgomery-Åsberg Depression Rating Scale). No significant result with respect to interleukin 6 and brain-derived neurotrophic factor was found. Furthermore, these biomarkers did not predict the antidepressant response or remission rates observed.

CONCLUSIONS

These findings enhance the understanding of the biological mechanisms behind the observed antidepressant effects of ayahuasca and encourage further clinical trials in adults with depression.

Cerebrospinal fluid proteome evaluation in major depressive disorder by mass spectrometry

BACKGROUND

Depression affects approximately 7.1% of the United States population every year and has an annual economic burden of over $210 billion dollars. Several recent studies have sought to investigate the pathophysiology of depression utilizing focused cerebrospinal fluid (CSF) and serum analysis. Inflammation and metabolic dysfunction have emerged as potential etiological factors from these studies. A dysregulation in the levels of inflammatory proteins such as IL-12, TNF, IL-6 and IFN-γ have been found to be significantly correlated with depression.

METHODS

CSF samples were obtained from 15 patients, seven with major depressive disorder and eight age- and gender-matched non-psychiatric controls. CSF protein profiles were obtained using quantitative mass spectrometry. The data were analyzed by Progenesis QI proteomics software to identify significantly dysregulated proteins. The results were subjected to bioinformatics analysis using the Ingenuity Pathway Analysis suite to obtain unbiased mechanistic insight into biologically relevant interactions and pathways.

RESULTS

Several dysregulated proteins were identified. Bioinformatics analysis indicated that the potential disorder/disease pathways include inflammatory response, metabolic disease and organismal injury. Molecular and cellular functions that were affected include cellular compromise, cell-to-cell signaling & interaction, cellular movement, protein synthesis, and cellular development. The major canonical pathway that was upregulated was acute phase response signaling. Endogenous upstream regulators that may influence dysregulation of proinflammatory molecules associated with depression are interleukin-6 (IL-6), signal transducer and activator of transcription 3 (STAT3), oncostatin M, PR domain zinc finger protein 1 (PRDM1), and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A).

CONCLUSIONS

The proteome profiling data in this report identifies several potential biological functions that may be involved in the pathophysiology of major depressive disorder. Future research into how the differential expression of these proteins is involved in the etiology and severity of depression will be important.

Longitudinal associations between circulating interleukin-6 and C-reactive protein in childhood, and eating disorders and disordered eating in adolescence

OBJECTIVE

Few studies have explored the association between inflammation and eating disorders and none used a longitudinal design. We investigated the association between serum-levels of interleukin 6 (IL-6) and C-reactive protein (CRP) measured in childhood and eating disorders and related behaviours and cognitions in adolescence in a large general population sample.

METHODS

We used data from the Avon Longitudinal Study of Parents and Children (ALSPAC). Our exposures were thirds of IL6 and CRP derived from serum measurements taken at age nine years, and outcomes were eating disorder diagnoses and self-reported disordered eating behaviours at ages 14, 16, and 18 years. We used univariable and multivariable multilevel logistic regression models adjusting for a number of potential confounders, including sex, fat mass, and pre-existing mental health difficulties.

RESULTS

Our sample included 3480 children. Those in the top third of CRP had lower odds of binge eating (odds ratio(OR):0.62, 95% confidence interval (CI):0.39,1.00,p "equals" 0.05) and fasting (OR:0.63, 95% CI:0.38,1.07,p "equals" 0.09) after adjustment for confounders. We also observed weak associations of comparable magnitude for purging, anorexia nervosa, and bulimia nervosa. We did not find any associations between levels of IL6 and any of the outcomes under study.

CONCLUSIONS

There was little evidence of an association between CRP and IL-6 and adolescent eating disorder outcomes. The inverse association observed between CRP and binge eating was unexpected, so caution is needed when interpreting it. One possible explanation is that higher CRP levels could have a protective role for disordered eating by affecting appetitive traits.

Antihypertensive Drugs and Risk of Depression: A Nationwide Population-Based Study

Hypertension, cardiovascular diseases, and cerebrovascular diseases are associated with an increased risk of depression, but it remains unclear whether treatment with antihypertensive agents decreases or increases this risk. The effects of individual drugs are also unknown. We used Danish population-based registers to systematically investigate whether the 41 most used individual antihypertensive drugs were associated with an altered risk of incident depression. Analyses of diuretics were included for comparisons. Participants were included in the study in January 2005 and followed until December 2015. Two different outcome measures were included: (1) a diagnosis of depressive disorder at a psychiatric hospital as an inpatient or outpatient and (2) a combined measure of a diagnosis of depression or use of antidepressants. Continued use of classes of angiotensin agents, calcium antagonists, and β-blockers was associated with significantly decreased rates of depression, whereas diuretic use was not. Individual drugs associated with decreased depression included 2 of 16 angiotensin agents: enalapril and ramipril; 3 of 10 calcium antagonists: amlodipine, verapamil, and verapamil combinations; and 4 of 15 β-blockers: propranolol, atenolol, bisoprolol, and carvedilol. No drug was associated with an increased risk of depression. In conclusion, real-life population-based data suggest a positive effect of continued use of 9 individual antihypertensive agents. This evidence should be used in guiding prescriptions for patients at risk of developing depression including those with prior depression or anxiety and patients with a family history of depression.

Comorbid depression in medical diseases

Depression is one of the most common comorbidities of many chronic medical diseases including cancer and cardiovascular, metabolic, inflammatory and neurological disorders. Indeed, the prevalence of depression in these patient groups is often substantially higher than in the general population, and depression accounts for a substantial part of the psychosocial burden of these disorders. Many factors can contribute to the occurrence of comorbid depression, such as shared genetic factors, converging biological pathways, social factors, health behaviours and psychological factors. Diagnosis of depression in patients with a medical disorder can be particularly challenging owing to symptomatic overlap. Although pharmacological and psychological treatments can be effective, adjustments may need to be made for patients with a comorbid medical disorder. In addition, symptoms or treatments of medical disorders may interfere with the treatment of depression. Conversely, symptoms of depression may decrease adherence to treatment of both disorders. Thus, comprehensive treatment plans are necessary to optimize care.

Antidepressive Effect of Arctiin by Attenuating Neuroinflammation via HMGB1/TLR4- and TNF-α/TNFR1-Mediated NF-κB Activation

Inflammation is a potential factor in the pathophysiology of depression. A traditional Chinese herbal medicine, arctiin, and its aglycone, arctigenin, are the major bioactive components in Fructus arctii and exhibit neuroprotective and anti-inflammatory activities. Arctigenin has been reported to have antidepressant-like effects. However, the antidepressant-like effects of arctiin, its precursor, remain unknown. In this study, we investigated the antidepressant-like effects of arctiin and its underlying mechanisms by in vivo and in vitro experiments in mice. Our results showed that arctiin significantly attenuated sucrose consumption and increased the immobility time in tail suspension and forced swimming tests. Arctiin decreased neuronal damage in the prefrontal cortex (PFC) of the brain. Arctiin also attenuated the levels of three inflammatory mediators, indoleamine 2,3-dioxygenase, 5-hydroxytryptamine, and dopamine, that were elevated in the PFC or serum of chronic unpredictable mild stress (CUMS)-exposed mice. Arctiin reduced excessive activation of microglia and neuroinflammation by reducing high mobility group box 1 (HMGB1)/toll-like receptor 4 (TLR4)- and tumor necrosis factor-α (TNF-α)/TNF receptor 1 (TNFR1)-mediated nuclear factor-kappa B (NF-κB) activation in the PFC of CUMS-exposed mice and HMGB1- or TNF-α-stimulated primary cultured microglia. These findings demonstrate that arctiin ameliorates depression by inhibiting the activation of microglia and inflammation via the HMGB1/TLR4 and TNF-α/TNFR1 signaling pathways.

The Pelvic Girdle Pain deadlock: 2. Topics that, so far, have remained out of focus

INTRODUCTION

In our preceding paper, we concluded that Pelvic Girdle Pain (PGP) should be taken seriously. Still, we do not know its causes. Literature reviews on treatment fail to reveal a consistent pattern, and there are patients who do not respond well to treatment. We designated the lack of progress in research and in the clinic as 'deadlock', and proposed a 'deconstruction' of PGP, that is to say, taking PGP apart into its relevant dimensions.

PURPOSE

We examine the proposition that PGP may emerge as local inflammation. Inflammation would be a new dimension to be taken into account, between biomechanics and psychology. To explore the consequences of this idea, we present four different topics that, so far, have remained out of focus. One: The importance of microtrauma. Two: Ways to counteract chronification. Three: The importance of sickness behaviour when systemic inflammation turns into neuroinflammation of the brain. And Four: The mainly emotional and cognitive nature of chronic pain, and how aberrant neuroinflammation may render chronic pain intractable. For intractable pain, sleep and stress management are promising treatment options.

IMPLICATIONS

The authors hope that the present paper helps to stimulate the flexible creativity that is required to deal with the biological and psychological impact of PGP. Measuring inflammatory mediators in PGP should be a research priority. It should be understood that the boundaries between biology and psychology are becoming blurred. Clinicians must frequently monitor pain, disability, and mood, and be ready to switch treatment whenever the patient does not improve.

Self-reported cannabis use and biomarkers of inflammation among adults in the United States

BACKGROUND

Cannabis is among the most frequently used substance in United States (U.S.). Studies evaluating the association between cannabis use and inflammation in humans have been few and have not explored potential sex-dependent effects.

OBJECTIVE

To examine the relationship between self-reported cannabis use and high-sensitivity C-reactive protein (hsCRP), Interleukin 6 (IL-6) and fibrinogen.

METHODS

We used Wave 1 of the Population Assessment of Tobacco and Health (PATH) - a nationally representative sample of adults in the U.S. Weighted linear regression models were used to determine associations of self-reported cannabis use with natural log-transformed hs-CRP, IL-6 and fibrinogen adjusting for sociodemographic and psychosocial factors.

RESULTS

Self-reported cannabis use, particularly cannabis use within the past 30 days, was associated with lower levels of each biomarker of systemic inflammation, although findings were imprecise. Specifically, in multivariable models, the associations between respondents who self-reported cannabis use in the past 30 days compared to never use was imprecise for hs-CRP (β= -0.15, 95% confidence interval (CI): -0.32, 0.00), IL-6 (β= - 0.02, 95% CI: -0.10, 0.05) and fibrinogen (β= - 0.01, 95% CI: -0.04, 0.02). We did not find that these associations differed significantly by sex.

DISCUSSIONS

Data from this nationally representative study suggest potential anti-inflammatory effects of recent cannabis use. Additional studies that biologically measure the THC and CBD concentrations of the cannabis used and employ prospective and or experimental study designs investigate cannabis and inflammation associations are needed.

Depression profilers and immuno-metabolic dysregulation: Longitudinal results from the NESDA study

BACKGROUND

Major depressive disorder (MDD) is linked to higher cardio-metabolic comorbidity that may in part be due to the low-grade inflammation and poorer metabolic health observed in MDD. Heterogeneity of MDD is however large, and immune-inflammatory and metabolic dysregulation is present in only part of the MDD cases. We examined the associations of four depression dimensional profilers (atypical energy-related symptom dimension, melancholic symptom dimension, childhood trauma severity, and anxious distress symptom dimension) with immuno-metabolic outcomes, both cross-sectionally and longitudinally.

METHODS

Three waves covering a 6-year follow-up (>7000 observations) of the Netherlands Study of Depression and Anxiety (NESDA) were used. Depression profilers were based on the Inventory of Depressive Symptomatology, the Beck Anxiety Inventory, and the Childhood Trauma index. An inflammatory index (based on IL-6 and CRP), a metabolic syndrome index (based on the five metabolic syndrome components), and a combination of these two indices were constructed. Mixed models were used for cross-sectional and longitudinal models, controlling for covariates.

RESULTS

Of the four depression profilers, only the atypical, energy-related symptom dimension showed robust associations with higher scores on the inflammatory, metabolic syndrome and combined inflammatory-metabolic indexes cross-sectionally, as well as at follow-up. The melancholic symptom dimension was associated with lower scores on the metabolic syndrome index both cross-sectionally and longitudinally.

CONCLUSION

The atypical energy-related symptom dimension was linked to poorer immune-inflammatory and metabolic health, while the melancholic symptom dimension was linked to relatively better metabolic health. Persons with high atypical energy-related symptom burden, representing an immuno-metabolic depression, may be the most important group to target in prevention programs for cardiometabolic disease, and may benefit most from treatments targeting immuno-metabolic pathways.

TNF-α and its soluble receptors mediate the relationship between prior severe mood episodes and cognitive dysfunction in euthymic bipolar disorder

BACKGROUND

Bipolar disorder (BD) is one of the most disabling mental health conditions in the world. Symptoms of cognitive impairment in BD contribute directly to occupational and social deficiencies and are very difficult to treat. Converging evidence suggests that BD patients have increased peripheral markers of inflammation. The hypothesis of neuroprogression in BD postulates that cognitive deficits develop over the course of the illness and are influenced by prior severe mood episodes, leading to wear-and-tear on the brain- however, there exists a paucity of data statistically testing a mediating role of immune molecules in cognitive dysfunction in BD.

METHODS

This is a cross-sectional study. We measured serum levels of tumor necrosis factor alpha (TNF-α), and soluble (s) TNF receptors one and two (sTNF-R1 and sTNF-R2) in 219 euthymic BD patients and 52 Healthy Controls (HCs). Structural equation modeling (SEM) was used for the primary purpose of assessing whether TNF markers (measured by the multiple indicators TNF-α, sTNF-R1 and sTNF-R2) mediate the effect or number of prior severe mood episodes (number of prior psychiatric hospitalizations) on cognitive performance.

RESULTS

BD and HC groups did not differ on circulating levels of TNF molecules in the present study. However, we found higher sTNF-R1 concentration in 'late-stage' BD illness (>1 prior psychiatric hospitalization) compared to those in early stage illness. In the subsequent SEM, we found that the model fits the data acceptably (Chi-square = 49.2, p = 0.3), and had a 'close fit' (RMSEA = 0.02, PCLOSE = 0.9). Holding covariates constant (age, sex, premorbid IQ, education, and race), we found that the standardized indirect effect was significant, p = 0.015, 90%CI [-0.07, -0.01], indicating that the estimated model was consistent with peripheral TNF markers partially mediating a causal effect of severe mood episodes on executive function.

CONCLUSIONS

Our results indicate that circulating levels of TNF molecules partially mediate the relationship between prior severe mood episodes and executive function in BD. These results may implicate TNF variables in the neuroprogressive course of BD and could point to novel interventions for cognition.

Whole-blood expression of inflammasome- and glucocorticoid-related mRNAs correctly separates treatment-resistant depressed patients from drug-free and responsive patients in the BIODEP study

The mRNA expression signatures associated with the 'pro-inflammatory' phenotype of depression, and the differential signatures associated with depression subtypes and the effects of antidepressants, are still unknown. We examined 130 depressed patients (58 treatment-resistant, 36 antidepressant-responsive and 36 currently untreated) and 40 healthy controls from the BIODEP study, and used whole-blood mRNA qPCR to measure the expression of 16 candidate mRNAs, some never measured before: interleukin (IL)-1-beta, IL-6, TNF-alpha, macrophage inhibiting factor (MIF), glucocorticoid receptor (GR), SGK1, FKBP5, the purinergic receptor P2RX7, CCL2, CXCL12, c-reactive protein (CRP), alpha-2-macroglobulin (A2M), acquaporin-4 (AQP4), ISG15, STAT1 and USP-18. All genes but AQP4, ISG15 and USP-18 were differentially regulated. Treatment-resistant and drug-free depressed patients had both increased inflammasome activation (higher P2RX7 and proinflammatory cytokines/chemokines mRNAs expression) and glucocorticoid resistance (lower GR and higher FKBP5 mRNAs expression), while responsive patients had an intermediate phenotype with, additionally, lower CXCL12. Most interestingly, using binomial logistics models we found that a signature of six mRNAs (P2RX7, IL-1-beta, IL-6, TNF-alpha, CXCL12 and GR) distinguished treatment-resistant from responsive patients, even after adjusting for other variables that were different between groups, such as a trait- and state-anxiety, history of childhood maltreatment and serum CRP. Future studies should replicate these findings in larger, longitudinal cohorts, and test whether this mRNA signature can identify patients that are more likely to respond to adjuvant strategies for treatment-resistant depression, including combinations with anti-inflammatory medications.

[Immunopsychiatry and SARS-CoV-2 pandemic: Links and possible consequences]

OBJECTIVE

The SARS-CoV-2 (or COVID-19) pandemic has been propagating since December 2019, inducing a drastic increase in the prevalence of anxious and depressive disorders in the general population. Psychological trauma can partly explain these disorders. However, since psychiatric disorders also have an immuno-inflammatory component, the direct effects of the virus on the host's immune system, with a marked inflammatory response, but also the secondary inflammation to these psychosocial stressors, may cause the apparition or the worsening of psychiatric disorders. We describe here the probable immunopsychiatric consequences of the SARS-CoV-2 pandemic, to delineate possible screening actions and care that could be planned.

METHOD

Data from previous pandemics, and existing data on the psychopathological consequences of the SARS-CoV-2 pandemic, allowed us to review the possible immunopsychiatric consequences of the SARS-CoV-2 pandemic, on the gestational environment, with the risk of consecutive neurodevelopmental disorders for the fetus on one hand, on the children and adults directly infected being at increased risks of psychiatric disorders on the other hand.

RESULTS

As in previous pandemics, the activation of the immune system due to psychological stress and/or to infection during pregnancy, might lead to an increased risk of neurodevelopmental disorders for the fetus (schizophrenia and autism spectrum disorders). Furthermore, in individuals exposed to psychological trauma and/or infected by the virus, the risk of psychiatric disorders, especially mood disorders, is probably increased.

CONCLUSION

In this context, preventive measures and specialized care are necessary. Thus, it is important to propose a close follow-up to the individuals who have been infected by the virus, in order to set up the earliest care possible. Likewise, in pregnant women, screening of mood disorders during the pregnancy or the postpartum period must be facilitated. The follow-up of the babies born during the pandemic must be strengthened to screen and care for possible neurodevelopmental disorders.

Inflammatory markers in depression: A meta-analysis of mean differences and variability in 5,166 patients and 5,083 controls

IMPORTANCE

The magnitude and variability of cytokine alterations in depression are not clear.

OBJECTIVE

To perform an up to date meta-analysis of mean differences of immune markers in depression, and to quantify and test for evidence of heterogeneity in immune markers in depression by conducting a meta-analysis of variability to ascertain whether only a sub-group of patients with depression show evidence of inflammation.

DATA SOURCES

Studies that reported immune marker levels in peripheral blood in patients with depression and matched healthy controls in the MEDLINE database from inception to August 29th 2018 were examined.

STUDY SELECTION

Case-control studies that reported immune marker levels in peripheral blood in patients with depression and healthy controls were selected.

DATA EXTRACTION AND SYNTHESIS

Means and variances (SDs) were extracted for each measure to calculate effect sizes, which were combined using multivariate meta-analysis.

MAIN OUTCOMES AND MEASURES

Hedges g was used to quantify mean differences. Relative variability of immune marker measurements in patients compared with control groups as indexed by the coefficient of variation ratio (CVR).

RESULTS

A total of 107 studies that reported measurements from 5,166 patients with depression and 5,083 controls were included in the analyses. Levels of CRP (g = 0.71; 95%CI: 0.50-0.92; p < 0.0001); IL-3 (g = 0.60; 95%CI: 0.31-0.89; p < 0.0001); IL-6 (g = 0.61; 95%CI: 0.39-0.82; p < 0.0001); IL-12 (g = 1.18; 95%CI: 0.74-1.62; p < 0.0001); IL-18 (g = 1.97; 95%CI: 1.00-2.95; p < 0.0001); sIL-2R (g = 0.71; 95%CI: 0.44-0.98; p < 0.0001); and TNFα (g = 0.54; 95%CI: 0.32-0.76; p < 0.0001) were significantly higher in patients with depression. These findings were robust to a range of potential confounds and moderators. Mean-scaled variability, measured as CVR, was significantly lower in patients with depression for CRP (CVR = 0.85; 95%CI: 0.75-0.98; p = 0.02); IL-12 (CVR = 0.61; 95%CI: 0.46-0.80; p < 0.01); and sIL-2R (CVR = 0.85; 95%CI: 0.73-0.99; p = 0.04), while it was unchanged for IL-3, IL-6, IL-18, and TNF α.

CONCLUSIONS AND RELEVANCE

Depression is confirmed as a pro-inflammatory state. Some of the inflammatory markers elevated in depression, including CRP and IL-12, show reduced variability in patients with depression, therefore supporting greater homogeneity in terms of an inflammatory phenotype in depression. Some inflammatory marker elevations in depression do not appear due to an inflamed sub-group, but rather to a right shift of the immune marker distribution.

Inflammation as a treatment target in mood disorders: review

BACKGROUND

Mood disorders, i.e. major depressive disorder (MDD) and bipolar disorders, are leading sources of disability worldwide. Currently available treatments do not yield remission in approximately a third of patients with a mood disorder. This is in part because these treatments do not target a specific core pathology underlying these heterogeneous disorders. In recent years, abnormal inflammatory processes have been identified as putative pathophysiological mechanisms and treatment targets in mood disorders, particularly among individuals with treatment-resistant conditions.

AIMS

In this selective review, we aimed to summarise recent advances in the field of immunopsychiatry, including emerging pathophysiological models and findings from treatment ttrials of immunomodulatory agents for both MDD and bipolar disorders.

METHOD

We performed a literature review by searching Medline for clinical trials of immunomodulating agents as monotherapy or adjunctive treatments in MDD and bipolar disorders. Included studies are randomised controlled trials (RCTs), cluster RCTs or cross-over trials of immunomodulating agents that had an active comparator or a placebo-arm.

RESULTS

Current evidence shows an association between inflammation and mood symptoms. However, there is conflicting evidence on whether this link is causal.

CONCLUSIONS

Future studies should focus on identifying specific neurobiological underpinnings for the putative causal association between an activated inflammatory response and mood disorders. Results of these studies are needed before further treatment trials of immunomodulatory agents can be justified.

Physiological stress markers, mental health and objective physical function

OBJECTIVE

The observed poorer physical function in persons with mental disorders could partly be due to dysregulation in physiological stress systems. However, an integrated picture of the role of physiological stress systems on objective physical function is lacking. This study examined the association of multiple physiological stress systems with objective physical function, and explored whether these stress systems contribute to the relationship between depression/anxiety and poorer physical function.

METHODS

Data of 2860 persons of the Netherlands Study of Depression and Anxiety was used. Physical function was indicated by hand grip strength assessed using a hand-held dynamometer and lung function assessed using a peak flow meter. Inflammatory markers (CRP, IL-6, TNF-α), salivary cortisol (cortisol awakening response (AUCg, AUCi), evening cortisol) and ANS markers (heartrate, PEP, RSA) were determined. Depression/anxiety disorders were determined using psychiatric interviews. Linear regression analyses were adjusted for sociodemographics, health and lifestyle factors.

RESULTS

Higher inflammation levels were associated with lower hand grip strength (B_CRP = -0.21(SE = 0.06), p < .001) and lower lung function (B_CRP = -2.07(SE = 0.66), p = .002), B_TNF-α = -3.35(SE = 1.42), p = .022). Higher salivary cortisol levels were associated with lower lung function (B_{evening cortisol} = -2.22(SE = 0.59), p < .001). The association, in women, between depression/anxiety disorders and poorer physical function did not significantly diminish after adjustment for physiological stress markers.

CONCLUSION

This large cohort study showed that stress system dysfunction (especially the immune-inflammatory system and HPA-axis) contributes to poorer objective physical function. Stress system dysfunction did not explain the poorer physical function observed in persons with depression/anxiety disorders, suggesting that other pathways are involved to explain that association.

Minocycline and celecoxib as adjunctive treatments for bipolar depression: a multicentre, factorial design randomised controlled trial

BACKGROUND

Several small studies suggest that the adjunctive use of anti-inflammatory agents might improve depressive symptoms in bipolar disorder. However, there are few well designed, appropriately powered clinical trials assessing the efficacy of these novel treatment strategies. We aimed to assess the efficacy of adjunctive minocycline or celecoxib in this setting.

METHODS

This double-blind, 12-week, randomised, placebo-controlled trial was done in four outpatient psychiatric clinics in Pakistan. Eligible participants were adults (aged 18-65 years) with DSM-5 bipolar disorder (type I or II) and a major depressive episode. In a 2 × 2 factorial design, participants were randomly assigned (1:1:1:1) to receive either active minocycline plus active celecoxib, active minocycline plus placebo celecoxib, placebo minocycline plus active celecoxib, or placebo minocycline plus placebo celecoxib. The primary outcome was the mean change from baseline to week 12 in score on the 17-item Hamilton Depression Rating Scale (HAMD-17), assessed in all randomised participants (missing data were imputed and assumed to be missing at random). The trial was registered with ClinicalTrials.gov, NCT02703363.

FINDINGS

266 (17%) of 1542 patients assessed between May 1, 2016, and March 31, 2019, were randomly assigned to receive minocycline plus celecoxib (n=68), minocycline plus placebo (n=66), celecoxib plus placebo (n=66), or placebo plus placebo (n=66). From baseline to week 12, depressive symptoms as per HAMD-17 reduced in all four groups (from 24·5-25·2 to 11·3-12·8), but these reductions did not differ significantly between the groups. In terms of main effects, reductions in HAMD-17 did not differ for patients treated with minocycline (mean adjusted difference vs non-minocycline 1·48 [95% CI -0·41 to 3·36]; p=0·123) or for celecoxib (mean adjusted difference vs non-celecoxib -0·74 [-2·61 to 1·14]; p=0·443). Rates of serious adverse effects did not differ between groups (31 participants had a manic switch, two self-harmed, and one died in a motor vehicle accident).

INTERPRETATION

We found no evidence that minocycline or celecoxib was superior to placebo for the treatment of bipolar depression. This large trial casts doubt on the potential therapeutic benefits of adjunctive anti-inflammatory drugs for the acute management of bipolar depression.

FUNDING

Stanley Medical Research Institute.

Higher handgrip strength predicts a lower risk of depressive symptoms in rural Chinese populations

BACKGROUND

The longitudinal associations between handgrip strength (HGS) and depressive symptoms remain unclear, especially in developing countries. The aim of this cohort study was to explore the associations between HGS and the incidence of depressive symptoms in China.

METHODS

This prospective cohort study enrolled 8470 participants living in 450 urban communities and rural villages within 28 provinces of China. Depressive symptoms were assessed using the 10-item Center for Epidemiological Studies Depression Scale. Cox proportional hazards regression models were used to examine the associations between baseline HGS and the incidence of depressive symptoms.

RESULTS

During the following period (mean follow-up, 3.75 years; 95% confidence interval [CI], 3.73-3.76 years), 2,027 (23.93%) out of 8470 participants developed depressive symptoms. The risk of depressive symptoms decreased progressively with both increasing weighted HGS (P for trend = 0.04) and absolute HGS (P for trend < 0.001) after multivariate-adjustments. Compared with participants in the lowest quartiles of weighted and absolute HGS, the multivariate-adjusted hazard ratios (HRs) (95% CIs) of depressive symptoms for participants in the highest quartiles were 0.83 (0.71, 0.98) and 0.74 (0.62, 0.89), respectively. The interaction terms of weighted HGS-place of residence (P for interaction < 0.001) and absolute HGS-place of residence (P for interaction = 0.03) were both significant. Higher weighted and absolute HGS were associated with a lower incidence of depressive symptoms for participants living in rural villages but not urban communities.

CONCLUSIONS

The results suggest that HGS predicts a lower risk of depressive symptoms in Chinese rural populations.

The Association Between Vascular Inflammation and Depressive Disorder. Causality, Biomarkers and Targeted Treatment

Diabetes, obesity, atherosclerosis, and myocardial infarction are frequently co-morbid with major depressive disorder. In the current review, it is argued that vascular inflammation is a factor that is common to all disorders and that an endothelial dysfunction of the blood-brain barrier could be involved in the induction of depression symptoms. Biomarkers for vascular inflammation include a high plasma level of C-reactive protein, soluble cell-adhesion molecules, von Willebrand factor, aldosterone, and proinflammatory cytokines like interleukin-6 or tumor necrosis factor α. A further possible biomarker is flow-mediated dilation of the brachial artery. Treatment of vascular inflammation is expected to prevent or to reduce symptoms of depression. Several tentative treatments for this form of depression can be envisioned: eicosapentaenoic acid (EPA), valproate, Vagus-nerve stimulation, nicotinic α7 agonists, and agonists of the cannabinoid CB₂-receptor.

Neurobiological findings underlying depressive behavior in Parkinson's disease: A review

Parkinson's disease (PD) is one of the most prevalent neurodegenerative diseases in the world with a harmful impact on the quality of life. Although its clinical diagnosis is based on motor symptoms such as resting tremor, postural instability, slow gait, and muscle stiffness, this disorder is also characterized by the presence of early emotional impairment, including features such as depression, anxiety, fatigue, and apathy. Depression is the main emotional manifestation associated with PD and the mechanisms involved in its pathophysiology have been extensively investigated however, it is not yet completely elucidated. In addition to monoaminergic imbalance, immunological and gut microbiota changes have been associated with depression in PD. Besides, a patient group appears be refractory to the treatment available currently. This review emphasizes the mainly neuromolecular findings of the PD-associated depression as well as discuss novel and potential pharmacological and non-pharmacological therapeutic strategies.

PET imaging shows no changes in TSPO brain density after IFN-α immune challenge in healthy human volunteers

Depression is associated with peripheral inflammation, but its link with brain microglial activity remains unclear. In seven healthy males, we used repeated translocator protein-Positron Emission Tomography (TSPO-PET) dynamic scans with [11C]PBR28 to image brain microglial activation before and 24 h after the immune challenge interferon (IFN)-α. We also investigated the association between changes in peripheral inflammation, changes in microglial activity, and changes in mood. IFN-α administration decreased [11C]PBR28 PET tissue volume of distribution (Vt) across the brain (-20 ± 4%; t6 = 4.1, p = 0.01), but after correction for radioligand free-plasma fraction there were no longer any changes (+23 ± 31%; t = 0.1, p = 0.91). IFN-α increased serum IL-6 (1826 ± 513%, t6 = -7.5, p < 0.001), IL-7 (39 ± 12%, t6 = -3.6, p = 0.01), IL-10 (328 ± 48%, t6 = -12.8, p < 0.001), and IFN-γ (272 ± 64%, t6 = -7.0, p < 0.001) at 4-6 h, and increased serum TNF-α (49 ± 7.6%, t6 = -7.5, p < 0.001), IL-8 (39 ± 12%, t6 = -3.5, p = 0.013), and C-reactive protein (1320 ± 459%, t6 = -7.2, p < 0.001) at 24 h. IFN-α induced temporary mood changes and sickness symptoms after 4-6 h, measured as an increase in POMS-2 total mood score, confusion and fatigue, and a decrease in vigor and friendliness (all p ≤ 0.04). No association was found between changes in peripheral inflammation and changes in PET or mood measures. Our work suggests that brain TSPO-PET signal is highly dependent of inflammation-induced changes in ligand binding to plasma proteins. This limits its usefulness as a sensitive marker of neuroinflammation and consequently, data interpretation. Thus, our results can be interpreted as showing either that [11C]PBR28 is not sensitive enough under these conditions, or that there is simply no microglial activation in this model.

Depression following graft-versus-host disease in a patient with acute lymphoblastic leukaemia: A case report

There is increasing evidence to suggest an association between depression and inflammation, with patients suffering from immune mediated-disorders exhibiting higher levels of depression. Inflammation in depression is a potential target for the development of novel treatment strategies. The present study presents a clinical case in which a patient with an underlying inflammatory condition acutely developed a severe depressive episode resulting in a sudden, dramatic change in their clinical picture. This case, with no similar case reports being in the literature thus far, at least to the best of our knowledge, highlights the increasing consideration that there may be a causative role between neuro-inflammation and depression. This study reports the case of a 40-year-old male with acute lymphoblastic leukaemia (ALL) and no previous psychiatric history, who developed an acute onset of a severe depressive episode in the context of the immune-mediated graft-versus-host disease (GVHD). GVHD is a complication of allogeneic hematopoietic cell transplantation, which the patient had undergone, for the treatment of his ALL. The rapid onset of depression could be explained by the neuroinflammatory processes occurring in GVHD. This provides a clinical example for the possible role of the immune system in depression, and clinicians should be aware of this association.

Brain 5-HT Deficiency Prevents Antidepressant-Like Effects of High-Fat-Diet and Blocks High-Fat-Diet-Induced GSK3β Phosphorylation in the Hippocampus

Obesity is associated with an increased risk of depression and anxiety disorders, but the nature of the relationship(s) between obesity and mental illness remains highly controversial. Some argue that depression and anxiety lead to increased consumption of "comfort foods," the intake of which reduces negative affect and promotes obesity. In contrast, others have theorized that negative affect results from chronic excessive consumption of highly palatable foods. The brain serotonin (5-HT) system has long been implicated in both the development and treatment of mental illness. Preclinical studies have shown that low brain 5-HT exacerbates depression- and anxiety-like behaviors induced by stress and blocks reductions in depression-like behavior induced by antidepressants, but the effects of brain 5-HT deficiency on responses to high-fat diet (HFD) have not been explored. The current work used genetically modified mice to evaluate the effects of low 5-HT on behavioral and molecular alterations induced by chronic exposure to HFD. Our results reveal that HFD decreases depression-like behavior and increases some anxiety-like behaviors in wild-type (WT) mice. However, genetic brain 5-HT deficiency blocks HFD-induced reductions in forced swim immobility and prevents HFD-induced increases in hippocampal GSK3β phosphorylation despite having no significant effects on HFD-induced changes in body weight or anxiety-like behavior. Together, our results suggest that brain 5-HT deficiency significantly impacts a subset of behavioral and molecular responses to HFD, a finding that could help explain the complex relationships between obesity and mental illness.